1. Field of the Invention
The invention relates to a loom with pneumatic weft thread insertion.
2. Description of the Prior Art
Looms with pneumatic weft thread insertion are known from the prior art in which the weft insertion is carried out either by means of a pivotable insertion device mounted on the reed or by means of an insertion device of fixed position mounted on the machine frame.
The looms with a pivotable insertion device have disadvantages. The respectively inserted weft thread is clamped in the region of the reed beat-up and cut so that the setting of the blowing nozzles in the insertion position can only take place during the resetting of the reed which in particular restricts the number of blowing nozzles and moreover makes a special control necessary. Through the to and fro movement of the reed provided with the insertion device relatively high inertial forces are produced which lead to undesired oscillations of the moved system and the weft threads are set in uncontrolled oscillations during this supply from the thread feeder into the blowing nozzles so that they cross one another and become caught up with one another. The air lines and the actuating apparatus are subjected to high mechanical loading which in particular makes a complicated control necessary for the actuating apparatus. From these disadvantages, lower speeds of rotation of the loom follow as a result of a higher tendency to break down, which is associated with a loss of productivity. Furthermore, it has proved to be disadvantageous that a shear is mounted on the machine frame and actuated via separate drive means, which has the consequence of a greater complexity apparatus-wise. The use of a thread clamp with active clamping, in which at least one clamping member is actively actuated, represents a further disadvantage. Thread breakages increasingly occur, in particular with fine threads.
The invention is based on the object of so improving a loom with pneumatic weft insertion that the named disadvantages do not occur.